Information processing method and apparatus

ABSTRACT

Information processing method and apparatus for original image protection in a simple manner at a low cost. When data is stored, a desired key code is inputted from an operation unit. An address conversion unit converts an address from an address output unit designating a storage position of a frame memory into a physical address of the frame memory based on the input desired key code, and the data is stored into a storage area of the frame memory designated by the converted physical address. As the data stored in the frame memory is held in this manner, even if the data is read out, an original cannot be reproduced as long as address conversion algorithm is unknown. Further, before the key code inputted from the operation unit is sent to the address conversion unit, it is shuffled in a key register. Thus key code security is improved.

FIELD OF THE INVENTION

The present invention relates to information processing method andapparatus, and more particularly, to information processing method andapparatus for prevention against original image reproduction from imagedata.

BACKGROUND OF THE INVENTION

Generally, when image information is stored into a memory, gray scalelevels of respective pixels are obtained as numerical values and thedata is stored in a predetermined order in continuous memory areas.

Further, the data string format upon storage of pixel information intomemory differs in accordance with format or implementation of dataprocessing algorithm of device to input images to a frame memory ordevice to output images from the memory, however, memory access isalways made in accordance with the same procedure inside the device.

That is, when pixel information stored in a particular address isaccessed, the same address value is always used.

Accordingly, in an image processing apparatus having a conventionalstorage device, there is a strong linkage between the content of theframe memory and an original image. In this case, if the content of theframe memory can be obtained or referred to by any means, the originalimage can be comparatively easily reproduced even though the procedureupon image data generation is not known.

However, this fact is very inconvenient in consideration of imageinformation security.

For example, when the content of frame memory is stored in a file inanother place or transferred to another place via a network, a thirdperson may have an opportunity to access the image data during such datatransfer which is often performed as daily work. As a result, there is ahigh probability that the image data is reproduced and the content ofthe original image is known.

Generally, confidential documents and the like are encrypted forprotection of the contents. However, encryption is generally complicatedand time-consuming processing, and further, installation of theencryption processing program is often difficult.

SUMMARY OF THE INVENTION

The present invention has been made in consideration of the abovesituation, and has its object to provide information processing methodand apparatus to realize a function to cause difficulty in analysis ofdata, even if the data is read by a third person, by a particular memoryaddressing method.

Another object of the present invention is to provide informationprocessing method and apparatus which realize a function to, especiallyupon image data storage, weaken the linkage between a frame memory andan original image by the particular memory addressing method, so as tocause difficulty in reproduction of the original image.

According to the present invention, to solve the above objects, providedis an information processing apparatus for storing data into storagemeans, comprising: key input means for inputting a desired key code;address conversion means for converting a first address designating astorage position of the storage means for holding the data to a secondaddress based on the desired key code inputted by the input means; and

-   -   storage control means for storing the data in a storage area of        the storage means designated by the second address obtained by        the address conversion means.

In the information processing, the address conversion means performsmutually reversible conversion between the first address and the secondaddress by the same key code. Further, the address conversion meansinterchanges several address lines of the first address based on thedesired key code inputted by the key input means to generate the secondaddress. Further, if the data is image data, the address conversionmeans performs address conversion so as to interchange positions of apredetermined areas divided from the image.

Further, the information processing apparatus further comprises key codeconversion means for generating a second key code from the input desiredkey code, and the address conversion means converts the first address tothe second address based on the second key code.

Further, The information processing apparatus further comprises inputselection means for selecting one input destination from plural datainput destinations, and data from the input destination selected by theinput selection means is stored into the storage means.

Further, in the information processing apparatus, the plural data inputdestinations include a scanner, a large-capacity storage device and acommunication device.

Further, the information processing apparatus further comprises outputselection means for selecting one output destination from plural dataoutput destinations, and data read from the storage means is outputtedto the output destination selected by the output selection means.

Further, in the information processing apparatus, the plural data outputdestinations include a printer, a large-capacity storage device, adisplay and a communication device. Further, the data is image data.

Further, the information processing apparatus further comprises ascanner for inputting data to be stored in the storage means and aprinter for outputting data stored in the storage means, and theinformation processing apparatus operates as a copying machine. Further,in the information processing apparatus a scanner or communicationdevice can be selected as an input source for inputting data to bestored in the storage means, and the communication device and a printercan be selected as an output destination for outputting data from thestorage means, further, the information processing apparatus operates asa facsimile machine.

Further, the information processing apparatus further comprises addressconversion designation means for designating execution or non-executionof address conversion by the address conversion means.

Further, provided is a data security method for the informationprocessing apparatus, comprising the steps of: for encryption, storinginput data into the storage means while converting an address by theaddress conversion means based on the desired key code inputted from thekey input means, and outputting the data as encrypted data to theoutside and holding the data; and for decryption, storing the held dataas input data into the storage means while converting the address by theaddress conversion means based on the same key code as the desired keycode inputted from the key input means, and outputting the data asdecrypted data to the outside.

Further, provided is a data security method for the informationprocessing apparatus, comprising the steps of: for encryption, storingthe key code and input data into the storage means while converting anaddress by the address conversion means based on the desired key codeinputted from the key input means, and outputting them as encrypted datato the outside and holding the data; and for decryption, storing theheld data as input data into the storage means while converting theaddress by the address conversion means based on the same key code asthe desired key code reproduced from the held data, and outputting thedata as decrypted data to the outside.

Further, provided is an information processing for storing data intostorage means, comprising: a key input step of inputting a desired keycode; an address conversion step of converting a first addressdesignating a storage position of the storage means for holding the datato a second address based on the desired key code inputted at the inputstep; and a storage control step of storing the data in a storage areaof the storage means designated by the second address obtained at theaddress conversion step.

In the information processing method, at the address conversion step,mutually reversible conversion is performed between the first addressand the second address by the same key code. Further, at the addressconversion step, several bits of the first address are interchangedbased on the desired key code inputted at the key input step, togenerate the second address. Further, at the address conversion step, ifthe data is image data, address conversion is performed so as tointerchange positions of a predetermined areas divided from the image.

Further, the information processing method further comprises a key codeconversion step of generating a second key code from the input desiredkey code, and at the address conversion step, the first address isconverted to the second address based on the second key code. Further,the data is image data.

Further, provided is a security method in use of the informationprocessing method in a printer, comprising the steps of: encryptingreceived image data by the information processing method andprint-outputting the data; and reading the print-outputted encrypteddata by a scanner or copying machine capable of decryption in accordancewith the same key as that used in encryption by the informationprocessing method.

Further, provided is a security method in use of the informationprocessing method in a scanner, comprising the steps of: encrypting readimage data by the information processing method; and print-outputting ordecoding the encrypted data by a printer or computer capable ofdecryption in accordance with the same key as that used in encryption bythe information processing method.

Further, provided is a security method in use of the informationprocessing method in a copying machine, comprising the steps of:encrypting read image data by the information processing method andprint-outputting the data; and reading the print-outputted encrypteddata in accordance with the same key as that used in encryption by theinformation processing method.

Further, provided is a security method in use of the informationprocessing method in a facsimile machine, comprising the steps of:encrypting read image data by the information processing method andtransmitting the data; and decrypting the received encrypted data inaccordance with the same key as that used in encryption by theinformation processing method and print-outputting the data.

Further, the security method further comprises the steps of:print-outputting the received encrypted data; and reading theprint-outputted encrypted data, decrypting the data in accordance withthe same key as that used in encryption by the information processingmethod and print-outputting the data.

Further, provided is a security method in use of the informationprocessing method in a communication device, comprising the steps of:encrypting data by the information processing method and transmittingthe data; and decrypting the received encrypted data in accordance withthe same key as that used in encryption by the information processingmethod and print-outputting the data. Further, the key is embedded in anencryption key to be transmitted.

Further, provided is a security method in use of the informationprocessing method in a computer, comprising the steps of: encryptingdata by the information processing method and storing the data; anddecrypting the stored encrypted data in accordance with the same key asthat used in encryption by the information processing.

Further, provided is a storage medium for storing an informationprocessing program in case of storing data into storage means in acomputer-readable format, wherein the information processing programincludes at least an address conversion step of converting a firstaddress designating a storage position of the storage means for storingthe data into a second address based on an input desired key code.

Further, in the storage medium, the information processing programfurther includes: a key input step of inputting a desired key code; anda storage control step of storing the data into a storage area of thestorage means designated by the second address obtained at the addressconversion step. Further, at the address conversion step, mutuallyreversible conversion is performed between the first address and thesecond address by the same key code. Further, at the address conversionstep, wherein at the address conversion step, several bits of the firstaddress are interchanged based on the desired key code inputted at thekey input step, to generate the second address.

Other features and advantages of the present invention will be apparentfrom the following description taken in conjunction with theaccompanying drawings, in which like reference characters designate thesame name or similar parts throughout the figures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention and,together with the description, serve to explain the principles of theinvention.

FIG. 1 is a block diagram showing the basic construction of aninformation processing apparatus according to a first embodiment of thepresent invention;

FIG. 2 is a flowchart showing processing for storing image data into aframe memory of the information processing apparatus according to thefirst embodiment;

FIG. 3 is a flowchart showing processing for reading image data from theframe memory of the information processing apparatus according to thefirst embodiment;

FIG. 4 is a block diagram showing in detail an address conversion unitof the first embodiment;

FIG. 5 is a block diagram showing the basic construction of theinformation processing apparatus according to a second embodiment of thepresent invention;

FIG. 6 is a flowchart showing processing for reading image data from theframe memory of the information processing apparatus according to thesecond embodiment; and

FIG. 7 is a block diagram showing the basic construction of theinformation processing apparatus according to a third embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will now be described indetail in accordance with the accompanying drawings.

First Embodiment

FIG. 1 is a block diagram showing the construction of an informationprocessing apparatus to which a first embodiment of the presentinvention is applied.

The information processing apparatus of the embodiment has a function toscan an original document and store image data into a large-capacitystorage device, and a function to search the large-capacity storagedevice for a target document and print-output the document from anoutput device such as a printer, in accordance with necessity.

In FIG. 1, a frame memory 1 stores image data which is an object ofprocessing.

An image input selector 2 designates a device as an input source ofimage data to be inputted into the frame memory 1 such as an imagescanner 2000 or a large-capacity storage device 1000. A communicationdevice may be included in the input sources.

Further, an image output selector 8 designates an output destination forimage data read out of the frame memory 1, such as a printer 1001, thelarge-capacity storage device 1000 or a display monitor 1002. Thecommunication device may be included in the output destination devices.

An address converter 3, as an element characteristic of the presentembodiment, converts a physical address to designate a data storageposition on the frame memory 1. The address converter 3 has an operationunit 4, a key register 5 and an address conversion unit 6.

The operation unit 4 is a data input device having a keyboard, apointing device and the like.

The operation unit 4 accepts input of numeral as a conversion keyreferred to by the address conversion unit 6, from an operator. Theinput numeral, which is information as a key to generate addressconversion pattern to be described later, plays a role of encryption keyaccording to the present embodiment. Further, mode designation datadesignating a normal mode to access the frame memory 1 without addressconversion or an encryption mode to access the frame memory 1 withaddress conversion is inputted. The input numeral (encryption key) andthe mode designation data are stored into the key register 5. Further,an address to access the frame memory 1 or a designation addressdesignating an address range may be inputted.

Note that when the entire address range of the frame memory 1 is to beconverted, the designation address is not necessary. The modedesignation data and the numeral (encryption key) are transferred to theaddress conversion unit 6. The address conversion unit 6 performsprocessing in accordance with these data. Further, when the designationaddress is inputted, it is sent to an address output unit 7. The addressoutput unit 7 outputs an address to the address conversion unit 6 basedon the designation address to designate the address or address range.The address to access the frame memory or designation addressdesignating address range may be inputted into the address output unit 7from an image input unit or other external memory controller than theoperation unit 4.

When image data inputted via the image input selector 2 is stored intothe frame memory 1, if the mode designation data designating the normalmode is inputted from the key register 5, the address conversion unit 6outputs an address to the frame memory 1 based on the physical addressgenerated by the address output unit 7. In synchronization with theaddress output, the predetermined image data is provided to the framememory 1 via the image input selector 2, and the image data is stored.

On the other hand, if the encryption mode is designated, the addressconversion unit 6 performs conversion on the physical address providedfrom the address output unit 7 by using the numeral stored in the keyregister 5. Then, the address conversion unit 6 outputs the convertedaddress to the frame memory 1. In synchronization with the addressoutput, the predetermined image data is provided to the frame memory 1via the image input selector 2, and the image data is stored.

Accordingly, from hardware of an external device which accesses theframe memory 1, it appears that the data is written into the framememory 1 in a position corresponding to the physical address generatedby the address output unit 7. However, the position in which the data isactually written differs in accordance with key.

The address conversion mentioned above can be carried out by using aconversion table which can converts each address of the frame memory 1into another one, randomly and biunivoquely. The conversion process isperformed as follows, when the address and the key are provided, theaddress conversion unit 6 adds the address and the key, and inputs theresult of addition into the conversion table, then a converted addressis obtained as an output from the conversion table, wherein if the sumof the address and the key is greater than the maximum value ofaddresses of the frame memory 1, a value generated by subtracting themaximum value from the sum is provided to the conversion table.

By the above processing, the image data can be stored into the framememory 1 in a manner such that even if the image data in the framememory 1 is read from the outside, original image reproduction cannot bemade from the stored image data.

Next, when image data stored in the frame memory 1 is to be read, theaddress output unit 7 generates a read address and outputs it to theaddress conversion unit 6. If the normal mode is designated, the addressconversion unit 6 supplies the same address as that inputted from theaddress output unit 7 to the frame memory 1, and data in a positioncorresponding to the address is outputted from the frame memory 1 to theimage output selector 8.

As described above, if the encryption mode is designated, the addressconversion unit 6 converts the physical address provided from theaddress output unit 7 by using the numeral stored in the key register 5.Then the address conversion unit 6 outputs the converted address to theframe memory 1. In synchronization with the address output, the imagedata stored in the input address is read out and outputted to the imageoutput selector 8. The address conversion for image reading can becarried out by an invert conversion of the conversion for image storing.That is the provided address is converted to an address by referring theconversion table in a reverse way, the address for reading is obtainedby subtracting the key from the output of the conversion table, whereinif the output is smaller than key, a value generated by adding themaximum value of addresses of the frame memory 1 to the subtraction isprovided as the address for reading to the frame memory 1.

The image output selector 8 outputs the input image data to, e.g., thelarge-capacity storage device 1000. The large-capacity storage device1000 holds the data.

If the image data stored in the large-capacity storage device 1000 isprinted out from the printer 1000, for example, the image input selector2 selects the large-capacity storage device 1000 as an image data inputdestination, and the image output selector 8 selects the printer 1001 asan output destination.

To normally read image data from the frame memory 1, the above-describedkey inputted from the operation unit 4 or external device is necessary.

That is, when the image data is read from the frame memory 1, if a wrongkey is inputted, image data for normal reproduction of original imagecannot be outputted from the frame memory 1. Thus, the original imagereproduction from image data stored in the frame memory 1 can beprotected.

Next, the flowchart of FIG. 2 shows a processing operation for storingimage data into the frame memory 1 according to the present embodiment.

In FIG. 2, at step S1, the operation unit 4 inputs mode designation datadesignating the normal mode or the encryption mode.

At step S2, the operation unit 4 checks the input mode. If the inputmode is the normal mode, as it is not necessary to perform addressconversion, the process proceeds to step S10, while if the input mode isthe encryption mode, proceeds to step S3.

At step S3, the operation unit 4 inputs an encryption key as a cipher,and stores it into the key register 5. The encryption key is notnecessarily a numeral but may be an arbitrary alphabet string or thelike. However, in consideration of normal stand-alone business machines,as it is convenient to limit ten-keys as means for inputting the key,only numerals are inputted in this embodiment. Next, if necessary, theoperation unit 4 inputs a write designation address or addressdesignating a write section with respect to the frame memory 1, andtransmits the address to the address output unit 7. Note that if theentire area of the frame memory is to be subjected to writingprocessing, the input of designation address or writing section is notnecessary.

At step S4, the address conversion unit 6 inputs the encryption key fromthe key register 5, then converts an address outputted from the addressoutput unit 7 based on the encryption key, and supplies the convertedaddress to the frame memory 1.

In the encryption-key based address conversion, the address space beforethe conversion and that after the conversion must be in one-to-onecorrespondence. If only this condition is satisfied, any method ofencryption-key based address conversion is used. More specifically, theaddress conversion may be performed by using a function performingone-to-one mapping with regard to each element of the address space ofthe frame memory, or by address bit exchange by referring to aconversion table holding address bit exchange rules based on encryptionkey.

On the other hand, at step S10, as the normal mode is designated, theaddress conversion unit 6 outputs the address inputted from the addressoutput unit 7 to the frame memory 1 without any conversion. Note that ifthe address output unit 7 is included in an external device, step S10may be omitted.

At step S5, in the frame memory 1, in synchronization with the addressinput from the address conversion unit 6, image data sent from the imageinput selector 2 is stored into an internal cell of the address.

At step S6, if there is next address input from the address output unit7, the process proceeds to step S7, while if there is no address input,the process ends.

At step S7, if the current mode is the encryption mode, the processreturns to step S4 to repeat the processing by the address conversionunit 6. If the current mode is the normal mode, the process returns tostep S10 to repeat the processing by the address conversion unit 6.

Note that when image data in the encryption mode is written into theframe memory, a predetermined tag code indicating that the writing hasbeen made in the encryption mode may be written, with linkage to a pairof head address and end address before conversion, into a predeterminedfield of the frame memory. By using the tag code, it can be determinedlater whether corresponding image data has been stored in the encryptionmode or not by designating the head address before conversion andreferring to the field.

Further, in the above example, the step of address conversion (S4) andthe step of not performing address conversion (S10) are provided.However, it may be arranged such that in case of the encryption mode, anaddress conversion table is generated based on an encryption key, whilein case of the normal mode, address conversion is not performed. In thisarrangement, the processing in FIG. 2 can be more simplified.

Next, a processing procedure for reading image data from the framememory 1 will be described with reference to the flowchart of FIG. 3.

In FIG. 3, at step S1, mode designation data designating the normal modeor the encryption mode is inputted from the operation unit 4.

At step S12, the operation unit 4 checks the input mode. If the mode isthe normal mode, as address conversion is not necessary, the processproceeds to step S20, while if the mode is the encryption mode, theprocess proceeds to step S13. Note that if the entire address range ofthe frame memory area is to be converted, the input of designationaddress or section is not necessary.

At step S13, an encryption key is inputted from the operation unit 4,and the encryption key is stored into the key register 5. Further, aread out designation address or an address designating a read outsection with respect to the frame memory 1 is inputted from theoperation unit 4, and is transmitted to the address output unit 7.

At step S14, the encryption key is inputted from the key register 5 intothe address conversion unit 6. Then an address outputted from theaddress output unit 7 is converted based on the encryption key, and issupplied to the frame memory 1.

On the other hand, at step S20, as the normal mode is designated, theaddress conversion unit 6 outputs the address inputted from the addressoutput unit 7 to the frame memory 1 without any conversion.

At step S15, in the frame memory 1, in synchronization with the addressinput from the address conversion unit 6, image data is read out from aninternal cell of the address and sent to the image output selector 8.

At step S16, if there is next input from the address output unit 7 intothe address conversion unit 6, the process proceeds to step S17, whileif there is no input, the process ends.

At step S17, if the mode is the encryption mode, the process returns tostep S14 to repeat the processing by the address conversion unit 6. Ifthe mode is the normal mode, the process returns to step S20 to repeatthe processing by the address conversion unit 6.

Note that in the reading processing in FIG. 3, the address designationmay be performed from other external devices than the operation unit 4.In such case, step S10 may be omitted. Further, it may be arranged suchthat in case of the encryption mode, an address conversion table isgenerated based on an encryption key, while in case of the normal mode,address conversion is not performed. In this arrangement, the processingin FIG. 3 can be more simplified.

Next, the construction of the address conversion unit 6 will bedescribed with reference to FIG. 4. Note that FIG. 4 also shows relatedprocessing units.

Referring to FIG. 4, the frame memory 1 has a 16 Mbyte capacity, where 1byte is used for storing 256 level single-color data. For example, theframe memory 1 can hold raster-scanned 4096×4096 pixel imageinformation.

Further, a 24-bit (8 bits×3) code corresponding to an encryption keyinputted from the operation unit 4 is inputted from the key register 5.

Further, a 24-bit frame address is inputted from the address output unit7.

Note that the present invention is not limited to these numbers of bits.

A several digit decimal integer numerical value is inputted by a userfrom the operation unit 4, then the numerical value is converted into ahexadecimal number, and stored into the key register 5. From a bitstring constructing the register, arbitrary 8 bits are extracted, andthree patterns are generated. The generated respective 8-bit data areinputted and stored into respective tables 6 a to 6 c.

The data stored in the respective tables 6 a to 6 c are used as keysdesignating conversion patterns to the converters 6 d to 6 f.

The address conversion unit 6 performs address conversion in threesteps.

The converter 6 d performs conversion for 12 bits corresponding to thelower order address. At this time, the conversion processing may beperformed in 1-pixel units, however, in actual image information, ifaddress conversion is performed by greater block (n×n), reproduction oforiginal image information is sufficiently difficult from the convertedimage information.

Accordingly, in this example, to simplify circuits around the converter,16-pixel address conversion is performed by address-converting onlyhigher order 8 bits without conversion of lower order 4 bits.

The address conversion by the converter 6 d corresponds to interchanging256 horizontal stripe areas (horizontally-continuous 16 pixel areas) inthe horizontal direction, in the 4096×4096 pixel image information onthe frame memory, in accordance with the content indicated by the table6a.

On the other hand, the address conversion by the converter 6 fcorresponds to interchanging 256 vertical stripe areas(vertically-continuous 16 pixel areas) in the vertical direction inaccordance with the table 6c.

The address conversion by the converter 6 e corresponds to separatingthe image into 256×256 areas (vertically- and horizontally-continuous 16pixel areas) and interchanging them in accordance with the table 6b.

As a result, these three address conversion make reproduction oforiginal image information sufficiently difficult if image informationstored in the frame memory 1 is read out by an address from the addressoutput unit 7.

In FIG. 4, the tables and the converters are separately provided,however, as long as address conversion is made in accordance with keydata, the present invention is not limited to this arrangement. Forexample, to simplify the circuit construction, it is preferable toconstruct a look-up table by using a programmable logic array, to obtaina conversion address from the table, with 8-bit information from the keyregister 5 and address from the address output unit 7 as input. Further,to improve security, it is preferable to sequentially change theconversion method in the address conversion unit 6. Further, in suchcase it is preferable to realize the address conversion with software.

If address conversion is not performed, the input address from theaddress output unit 7 is selected by multiplexers 6 h and 6 g, and thehigher order and lower order addresses in the frame memory 1 a arerespectively designated.

Thereafter, data is sequentially read out from the frame memory 1 fromthe head address, and stored in the large-capacity storage device 1000or the like via the image output selector 8.

The encryption processing upon storage of image data into thelarge-capacity storage device 1000 or the like is as described above.Upon image reproduction, image information is temporarily stored intothe frame memory 1 from the head address, then the data is read from theframe memory 1 by using an address converted by the address conversionunit 6 as in the case of storage, outputted from the address output unit7, and the image is reproduced based on the data.

In this case, the management of encryption key is important. If thealgorithm for generating output bits from the address conversion unit 6or key register 5 is unknown, the key may be included in encrypted imagedata. Preferably, the encryption key in this case is time-varying datasuch as processing time. However, there is a possibility that the abovealgorithm is analyzed. To prevent the analysis of the algorithm, it isnecessary to frequently change the algorithm.

Second Embodiment

The second embodiment shows a processing procedure for writing imagedata into the frame memory 1 in a case where the above-described tagcode indicating type of the mode is written in a predetermined field ofthe frame memory 1 with linkage to a pair of head address and endaddress before conversion.

FIG. 5 shows the construction of the information processing apparatusaccording to the second embodiment. FIG. 5 differs from FIG. 1 in that apath to output data read from the frame memory 1 to the operation unit 4is added, but the other elements are identical to those in FIG. 1.Accordingly, the corresponding processing units have the same referencenumerals.

Next, a processing procedure for normally reading predetermined imagefrom the frame memory according to the present embodiment will bedescribed with reference to FIG. 6.

In FIG. 6, at step S61, the operation unit 4 inputs output head addressand end address from the frame memory 1 and writes them into the keyregister 5.

At step S62, the operation unit 4 outputs an address of predeterminedarea holding tag information to the address output unit 7. Further, themode designation data designating the normal mode is stored in the keyregister 5. The address output unit 7 outputs the address ofpredetermined area holding the tag information to the address conversionunit 6. As the mode designation data designating the normal mode isinputted from the key register 5, the address conversion unit 6 suppliesthe address inputted from the address output unit 7 to the frame memory1 without any conversion. Then tag related information stored in thesupplied address area is read from the frame memory 1 and sent to theoperation unit 4. The operation unit 4 searches the tag relatedinformation sent from the frame memory 1 for tag data related to theoutput head address inputted at step S61, and obtains the type of themode.

At step S63, the operation unit 4 determines the type of the modeobtained at step S61. If the mode is the normal mode, as addressconversion is not necessary, the process proceeds to step S70, while ifthe mode is the encryption mode, the process proceeds to step S64.

At step S64, an encryption key is inputted from the operation unit 4.Further, the operation unit 4 transmits a write designation address orwrite section designation address with respect to the frame memory 1 tothe address output unit 7.

At step S65, the operation unit 4 stores the encryption key inputted atstep S64 into the key register 5.

At step S66, the encryption key is inputted from the key register 5 intothe address conversion unit 6. Then, an address outputted from theaddress output unit 7 is converted based on the encryption key, and theconverted address is supplied to the frame memory 1.

On the other hand, at step S70, as the normal mode is designated, theaddress conversion unit 6 outputs the address inputted from the addressoutput unit 7 to the frame memory 1 without any conversion.

At step S67, in synchronization with the address input from the addressconversion unit 6, image data is read out from an internal cell of theaddress from the frame memory 1, and sent to the image output selector8.

At step S68, if there is next address input from the address output unit7, the process proceeds to step S69, while if there is no address input,the process ends.

At step S69, if the mode is the encryption mode, the process returns tostep S66, to repeat the processing. If the mode is the normal mode, theprocess returns to step S70 to repeat the processing.

The image-data read out (reproduction) processing procedure in thesecond embodiment is as described above.

Note that as in the case of the first embodiment, various changes may bemade in the construction of the address conversion unit 6 and encryptionkey management.

Third Embodiment

Next, the third embodiment will be described. In the first embodiment asshown in FIG. 1, the information processing apparatus is used foraddress conversion upon image storage and image reproduction as anindependent apparatus, however, the present invention is not limited tosuch purpose.

For example, if the information processing apparatus according to thepresent invention is applied to a frame memory of a copying machine, thecopying machine has an encryption function.

FIG. 7 shows the construction of a copying machine having an encryptionfunction.

In FIG. 7, in an image input unit 9, a shift correction device 9 bperforms positional correction on an image read from an input device(scanner) 9 a for preventing positional shift of original document on aplaten. Then the corrected image is stored into a frame memory 11.

Since the operations of address output unit 9 c, address converter 10and its internal modules are the same as those in FIG. 1, theexplanation of the operations will be omitted.

Further, data writing to the frame memory 11 is made with respect to anarea designated by an address converted in accordance with a similarprocedure to that described above.

The content of the frame memory 11 is finally read sequentially from thehead address, and is outputted from an output unit 12.

Generally, as the output unit of copying machine is a printer, a printedoutput can be obtained. As the printed output is encrypted in accordancewith a key inputted by a user from an operation unit 10 a, it isillegible. To reproduce the original image, the encrypted document isread again from the image input unit 9, and is outputted in a decryptionmode in accordance with the same key as that in the encryption. As themethod of generating a conversion address of the frame memory uponencryption and decryption is the same as that in FIG. 4, the explanationof the method will be omitted. Further, as described above, theencryption key may be included in a printed output for decryptionwithout input from the operation unit 10 a.

Further, in use of facsimile machine, as long as the machine has amemory to hold several pages of transmission document, encryption upontransmission is possible by providing the frame memory of theinformation processing apparatus according to the present invention. Inthis case, the encrypted document may be decrypted by an operator'sinputting a predetermined key upon printing of confidential document.

Further, the purpose of the present invention is not limited to theframe memory. For example, the invention can be applied to a method foraccessing a memory constructing a main storage device of a generalcomputer.

In this case, as an area holding secret information is accessed by usingaddress conversion by a key, even if the area is accessed by a thirdperson who does not know the key, the position of the information ornormal order of information cannot be obtained. Thus data security canbe improved.

Note that in the above construction of the information processingapparatus, the address conversion unit 6 is realized by circuits,however, processing equivalent to the processing by the addressconversion unit 6 can be realized by software program which is storedinto a memory and executed by a predetermined CPU. The advantage of thiscase is as described above.

As described above, an information storage device having an encryptionfunction can be realized by providing a memory constructing a framememory for storing an original image, adding a register and a converterto an address designation device, and providing means for performingconversion processing on a physical address inputted into the addressdesignation device by using the converter in accordance with a valuestored in the register.

Further, as described above, the frame memory addressing methodaccording to the present invention weakens the linkage between the framememory and an original image, and even if data is read by a thirdperson, causes difficulty in reproduction of original image.

The present invention can be applied to a system constituted by aplurality of devices (e.g., a host computer, an interface, a reader anda printer) or to an apparatus comprising a single device (e.g., a copymachine or a facsimile apparatus).

Further, the object of the present invention can be also achieved byproviding a storage medium storing program code for performing theaforesaid processes to a system or an apparatus, reading the programcode with a computer (e.g., CPU, MPU) of the system or apparatus fromthe storage medium, then executing the program.

In this case, the program code read from the storage medium realizes thefunctions according to the embodiments, and the storage medium storingthe program code constitutes the invention.

Further, the storage medium, such as a floppy disk, a hard disk, anoptical disk, a magneto-optical disk, CD-ROM, CD-R, a magnetic tape, anon-volatile type memory card, and ROM can be used for providing theprogram code.

Furthermore, besides aforesaid functions according to the aboveembodiments are realized by executing the program code which is read bya computer, the present invention includes a case where an OS (operatingsystem) or the like working on the computer performs a part or entireprocesses in accordance with designations of the program code andrealizes functions according to the above embodiments.

Furthermore, the present invention also includes a case where, after theprogram code read from the storage medium is written in a functionexpansion card which is inserted into the computer or in a memoryprovided in a function expansion unit which is connected to thecomputer, CPU or the like contained in the function expansion card orunit performs a part or entire process in accordance with designationsof the program code and realizes functions of the above embodiments.

In a case where the present invention is applied to the aforesaidstorage medium, the storage medium stores program code corresponding tothe flowcharts described in the embodiments.

The present invention is not limited to the above embodiments andvarious changes and modifications can be made within the spirit andscope of the present invention. Therefore, to appraise the public of thescope of the present invention, the following claims are made.

1. An information processing apparatus having a step of storing datainto storage means, comprising: key input means for inputting a desiredkey code; address receiving means for receiving a first physical addressdesignating a storage position for holding the data in the storagemeans; address conversion means for converting the first physicaladdress of the storage means into a second physical address of thestorage means based on the desired key code inputted by said inputmeans; and storage control means for storing the data at a storageposition of the storage means designated by the second physical addressobtained by said address conversion means.
 2. The information processingapparatus according to claim 1, wherein said address conversion meansperforms mutually reversible conversion between said first physicaladdress and said second physical address by the same key code.
 3. Theinformation processing apparatus according to claim 2, wherein saidaddress conversion means interchanges several address lines of saidfirst physical address based on the desired key code inputted by saidkey input means to generate said second physical address.
 4. Theinformation processing apparatus according to claim 2, wherein if saiddata is image data, said address conversion means performs addressconversion so as to interchange positions of a predetermined areasdivided from the image.
 5. The information processing apparatusaccording to claim 2, further comprising key code conversion means forgenerating a second key code from said input desired key code, whereinsaid address conversion means converts said first physical address tosaid second physical address based on said second key code.
 6. Theinformation processing apparatus according to claim 1, furthercomprising input selection means for selecting one input destinationfrom plural data input destinations, wherein data from the inputdestination selected by said input means is stored into said storagemeans.
 7. The information processing apparatus according to claim 4,wherein said plural data input destinations include a scanner, alarge-capacity storage device and a communication device.
 8. Theinformation processing apparatus according to claim 1, furthercomprising output selection means for selecting one output destinationfrom plural data output destinations, wherein data read from saidstorage means is outputted to the output destination selected by saidoutput selection means.
 9. The information processing apparatusaccording to claim 6, wherein said plural data output destinationsinclude a printer, a large-capacity storage device, a display and acommunication device.
 10. The information processing apparatus accordingto claim 1, wherein said data is image data.
 11. The informationprocessing apparatus according to claim 1, further comprising a scannerfor inputting data to be stored in said storage means and a printer foroutputting data stored in said storage means, wherein said informationprocessing apparatus operates as a copying machine.
 12. The informationprocessing apparatus according to claim 1, wherein a scanner orcommunication device can be selected as an input source for inputtingdata to be stored in said storage means, and wherein said communicationdevice and a printer can be selected as an output destination foroutputting data from said storage means, further wherein saidinformation processing apparatus operates as a facsimile machine. 13.The information processing apparatus according to claim 1, furthercomprising address conversion designation means for designatingexecution or non-execution of address conversion by said addressconversion means.
 14. A data security method for the informationprocessing apparatus in claim 1, comprising the steps of: forencryption, storing input data into said storage means while convertingan address by said address conversion means based on the desired keycode inputted from said key input means, and outputting the data asencrypted data to the outside and holding the data; and for decryption,storing said held data as input data into said storage means whileconverting the address by said address conversion means based on thesame key code as said desired key code inputted form said key inputmeans, and outputting the data as decrypted data to the outside.
 15. Adata security method for the information processing apparatus in claim1, comprising the steps of: for encryption, storing said key code andinput data into said storage means while converting an address by saidaddress conversion means based on the desired key code inputted fromsaid key input means, and outputting them as encrypted data to theoutside and holding the data; and for decryption, storing said held dataas input data into said storage means while converting the address bysaid address conversion means based on the same key code as said desiredkey code reproduced from said held data, and outputting said data asdecrypted data to the outside.
 16. An information processing method forstoring data into storage means, comprising: a key input step ofinputting a desired key code; an address receiving step of receiving afirst physical address designating a storage position for holding thedata in the storage means; an address conversion step of converting thefirst physical address of the storage means into a second physicaladdress of the storage means based on the desired key code inputted atsaid input step; and a storage control step of storing the data at astorage position of the storage means designated by the second physicaladdress obtained at said address conversion step.
 17. The informationprocessing method according to claim 16, wherein at said addressconversion step, mutually reversible conversion is performed betweensaid first physical address and said second physical address by the samekey code.
 18. The information processing method according to claim 16,wherein at said address conversion step, several bits of said firstphysical address are interchanged based on the desired key code inputtedat said key input step, to generate said second physical address. 19.The information processing method according to claim 17, wherein at saidaddress conversion step, if said data is image data, address conversionis performed so as to interchange positions of a predetermined areasdivided from the image.
 20. The information processing method accordingto claim 17, further comprising a key code conversion step of generatinga second key code from said input desired key code, wherein at saidaddress conversion step, said first physical address is converted tosaid second physical address based on said second key code.
 21. Theinformation processing method according to claim 16, wherein said datais image data.
 22. A security method in use of the informationprocessing method in claim 16 in a printer, comprising the steps of:encrypting received image data by said information processing method andprint-outputting the data; and reading the print-outputted encrypteddata by a scanner or copying machine capable of decryption in accordancewith the same key as that used in encryption by said informationprocessing method.
 23. A security method in use of the informationprocessing method in claim 16 in a scanner, comprising the steps of:encrypting read image data by said information processing method; andprint-outputting or decoding the encrypted data by a printer or computercapable of decryption in accordance with the same key as that used inencryption by said information processing method.
 24. A security methodin use of the information processing method in claim 16 in a copyingmachine, comprising the steps of: encrypting read image data by saidinformation processing method and print-outputting the data; and readingthe print-outputted encrypted data in accordance with the same key asthat used in encryption by said information processing method.
 25. Asecurity method in use of the information processing method in claim 16in a facsimile machine, comprising the steps of: encrypting read imagedata by said information processing method and transmitting the data;and decrypting the received encrypted data in accordance with the samekey as that used in encryption by said information processing method andprint-outputting the data.
 26. The security method according to claim25, further comprising the steps of: print-outputting the receivedencrypted data; and reading the print-outputted encrypted data,decrypting the data in accordance with the same key as that used inencryption by said information processing method and print-outputtingthe data.
 27. A security method in use of the information processingmethod in claim 16 in a communication device, comprising the steps of:encrypting data by said information processing method and transmittingthe data; and decrypting the received encrypted data in accordance withthe same key as that used in encryption by said information processingmethod and print-outputting the data.
 28. The security method accordingto claim 27, wherein said key is embedded in an encryption key to betransmitted.
 29. A security method in use of the information processingmethod in claim 16 in a computer, comprising the steps of: encryptingdata by said information processing method and storing the data; anddecrypting the stored encrypted data in accordance with the same key asthat used in encryption by said information processing.
 30. Aninformation processing program, embodied in a computer readable medium,for storing data into storage means in a computer-readable format, saidinformation processing program comprising: a key input step of inputtinga desired key code; an address receiving step of receiving a firstphysical address designating a storage position for holding the data inthe storage means; an address conversion step of converting the firstphysical address of the storage means into a second physical address ofthe storage means based on the desired key code inputted at said inputstep; and a storage control step of storing the data at a storageposition of the storage means designated by the second physical addressobtained at said address conversion step.
 31. The program according toclaim 30, wherein at said address conversion step, mutually reversibleconversion is performed between the first physical address and thesecond physical address by the same key code.
 32. The program accordingto claim 30, wherein at said address conversion step, several bits offirst physical address are interchanged based on the desired key codeinputted at said key input step, to generate the second physicaladdress.